Continuous maneuver based advanced driver assistance systems (ADAS), such as a lane change assistance system (LCAS), assist the driver, for example, before and during lane changes. These systems have the risk to act as a nagging guardian for the driver as soon as there is a mismatch between the system support and the driver's intention, and this may unduly annoy the driver. For instance, the driver intends to follow the vehicle ahead on a motorway but LCAS may continuously recommend a lane change maneuver to the left adjacent lane by e.g. haptic, visual, acoustic or active longitudinal/lateral interventions, in order to overtake the vehicle in front. To solve this mismatch between the system and driver behavior the detection of the driver's intention is essential (e.g. left lane change, follow vehicle). This drastically reduces the paternalism of the driver and thus increases the driver's acceptance and the effectiveness of such a system.
Furthermore, to realize a LCAS that analyzes different lane change alternatives (as depicted in FIG. 1), and recommends the best gap (considering safety and comfort aspects) which is in line with the driver's lane change intention, an early driver intention recognition is indispensable.
DE 10 2006 043 149 A1 discloses an integrated transverse and longitudinal guidance assistant for motor vehicles, which has a trajectory calculating unit to calculate a lane change trajectory with a given distance of a vehicle traveling in front. The time to line crossing (TLC) is calculated so that the driver's intention to change lanes may be determined by detecting the driver steering toward the left or right line marker and the TLC being smaller than a certain threshold. However, as the driver's intention to change lanes is detected only after the lane changing maneuver is initiated, the detection of the driver's intention may be too late for most of the ADAS applications. Furthermore, it is necessary that the lane marker must be detected continually.
DE 10 2005 022 663 A1 discloses a vehicle driver assistance method that alerts the vehicle operator by using a voice output when the current lane ends and the vehicle is required to filter into the traffic of the adjacent lane. The lane filtering situation is detected if the lane on which the vehicle is traveling ends. The detection signal controls an acoustic indication such as a voice output and/or visual indicator. This patent document also discloses an apparatus for assisting the vehicle operator in filtering into the traffic of the adjacent lane. The disclosure is however limited to this scenario, and is not transferable to other scenarios.
U.S. Pat. No. 7,363,140 discloses a lane changing assistant for motor vehicles that assists the vehicle operator in finding an available window in the adjacent lane and computing an acceleration strategy adjusted to the window. The lane changing decision is left to the vehicle operator, and the system computes the acceleration strategy when the decision is an acceptable one.
US 2008/0201050 A1 is directed to a system for detecting gaps in an adjacent lane on a multi-lane road. The system provides a human machine interface (HMI) to assist a vehicle operator change lanes. The detection of the vehicle operator's intension is based on a set of driver reactions, such as activation of a turn indicator, and the acceleration and deceleration of the ego vehicle and the distance to the vehicle ahead. As the vehicle operator's intension is detected from the turn indicator and motion of the ego vehicle, the detection of the vehicle operator's intension is necessarily delayed.
The prior art thus fails to provide a system for predicting an intention of a vehicle driver to change lanes which is capable of an adequately early detection to be implemented as an effective part of a ADAS because the prediction is based on the detection of the initiation of a lane changing or overtaking maneuver. If the prediction is based on the detection of available gaps or windows in the adjacent lane, the prediction may be made earlier, but the availability of gaps may not necessarily means that the vehicle driver wishes to change lanes.
The prior art, even if it is configured to detect a driver's intention to change lanes, focuses only on one factor as a criterion that determines the intention of the driver to change lanes. In view of this limitation of the prior art, the inventors have realized that a vehicle driver snakes a lane changing or overtaking decision based on a number of factors (motivators and inhibitors), such as:
Slow vehicle driving ahead
Decelerating vehicles driving ahead
Faster vehicle approaching from behind
End of lane
Obligation to drive on left or right lane (depending on left- or right-hand-traffic)
Narrow lane (e.g. during road works)
Lane changes due to selected route (e.g. provided by navigation system).
Thus, there is a need to solve the problems described above, and provide an early and reliable driver intention recognition or prediction which accounts for a plurality of reasons for lane change/overtaking maneuvers and decisions.